What is this on a rooster's foot ?

I have a rooster who is about a year old, he also has 4 other hens. He seems to have this weird thing nearly halfway up his leg on both of his legs. None of the hens have it, i'm slightly worried, do you know what it is ?

In the picture, i know they have the front 3 toes, then they have another one further back but further up the leg, there is this weird thing.

It's a spur, the older he gets the sharper it will get. He will use these to protect his hens from predators by attacking them with these. Depending on the disposition of the rooster they go after people, usually children. If they have a good disposition and are used to being handled they are fine.